In a conventional vacuum cleaner of a dust bag type, suctioned dust is accumulated in the dust bag made of a disposable paper. When the dust bag is filled with dust, the dust bag should be changed. Recently, there has been developed a so-called cyclone type dust collecting device in which suctioned air is spirally rotated to separate dust or the like having a relatively greater mass from the air by a centrifugal force without employing a disposable dust bag.
FIG. 6 shows a schematic cross sectional view of a conventional cyclone dust collecting device disclosed in U.S. Patent Laid-open Publication No. 2002/88078 A1.
In the conventional cyclone dust collecting device, air introduced through a suction port 925 into a cyclonic air flow chamber 923 vertically moves along the inner surface thereof. As a result, dust and the like having a relatively greater mass flows into a dust collection chamber 930 and the air is discharged from a discharge port 922 after passing through an inside of a filter unit 924.
However, in such a conventional cyclone dust collecting device, a part of air vertically moving in the cyclonic air flow chamber 923 flows into the dust collection chamber 930 to collide with dust accumulated in the dust collection chamber 930, thereby scattering the dust to flow back into the cyclonic air flow chamber 923. Further, the air flow in the cyclone dust collecting device is not smooth as a whole since there is no discharge passageway for the air introduced into the dust collection chamber 930.